Stratifying dehydrator



W. NIEREDITH.

STRATIFYING DEHYDRATR. APPLICATION FILED APR. 30, I92I.

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Patented Sept. 26, 1922.

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` WYNN MEREDITH, OF ALAMEDA, CALIFORNIA, ASSIGNOR TO PETROLEUM RECTIFY- ING COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

. STRATIFYING DEHYDRATOR.

Application led April 30,1921. Serial No. 465,909.

To .all whom t may concern:

Be it known that I, WYNN MEREDITH, a citizen of the United States, residing at Alameda, in the county of Alameda and State of California, have invented a new and useful Stratifying Dehydrator, of which the following is a specification. y

My invention relatesto dehydrators which are used for separating emulsified water from oil and it is particularly applicable to dehydrators used to separate water from petroleum emulsions.

The principal object of the invention is to provide a dehydrator which will be adapted` to treat oils of' widely different characteristics. Y

A further object of the `invention is to provide a dehydratoi' having a layer of high di-electric strength in the electric field.

A still further object of the invention is to provide a dehydrator in which the porcelain insulation is so ldisposed that it is kept clean by a current of dehydrated oil. l Further Vobjects and advantages will be made evident hereinafter.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a side elevation partly in section showing one form of my invention.

Fig. 2 is a plan view of same.

Fig. 3 is a diagram illustrating the char-l acter of the electric field.

Referring to these drawings, the apparatus illustrated consists of a dehydrator tank 11, a centrifugal pump 12 and a settling tank 13. The-tank 11 forms the dehydrator proper and is of cylindrical form -havingatight bottom 14 and a tight top 15.

Passing through the top is a porcelain insulator 20' which has a central opening throughwhich a conductor '21* passes,this conductor being attached to'a rod 22 which supports the inner electrodel 30. The tank 11 forms the outer grounded electrode. The inner electrode consists of a cylindrical shell 31 joined to an inverted funnel 32 at the bottom and to a draft tube 33 at the top.-

011e or more intermediate discs 34 maybe secured to the cylinder 31. A transformer -35 havino' a low tension primary 36 and a high tension secondary 37 is provided. One side of the secondary 37 is connected through a wire 138 with the tank 11 and the other side being connected through a wire 39 with the conductor 21. A reversing plate 40`vis and down by means of a cable' 53 and a winch 54. The pipe 52 is connected through a valve with'the suction side of the centrifugal pump 12 which may be conveniently driven by an electric motor 56. A by-pass pipe 57 controlled by a lvalve 58y connects the pipe 50 with the suction of the pump12. The pressure side of the pump is connected to a pipe 59 having a iow valve 60, this pipe 59 being connected to a nozzle 61 placed similarly inside the tank 11 and directed upwardly therein.

The method of operation is as followsz. rThe tanks 11 and 13 are rst filled wlth oil, any gas or air in the top of the tank 11 being relieved through a gas vent 70. As Asoon as the apparatus is filled with the oil to be treated the primary 36 is energized thus generating an alternating electro-motlve force of about 11,000 volts in the secondary 37, this electro-motive force being impressed between the tank 11 and its connected parts, and the inner electrode 30.v Intense electrostatic fields are set up between the edges of the members 32, 33 and 34 and the 1nner surface of the tank 11. fields ,tend to establish arcs or conductlng chains through the water particles thus tending to short-circuit the secondary 37. This short-circuiting tendency can be overcome byagitation which can be readily pro- `duced by the pump 12.

In starting the dehydrator, I prefer to.

close the valve 55 and to open the valve 58 -thus ,circulating fluid from the bottom of the tank 11 upwardly through the cylinder 31 and downwardly through the electric fields at the edges of the members 32, 33 and 34. The rate of jfiow can b e readily controlled by the valve 60 which is mampulated to control the rate of flow so that exceseive disruptive discharges do not take place in the electric fields. .Y The contents of lthe treater 11 are S0013 partially dehydrated These electrostatic to a sufficient degree. rllfhe valve 58 may then be closed and the valve 55 opened, the swing pipe 52 being' adjusted about as shown in the drawing. i il is now taken from the top of the settling tank 13 passing upwardly through the cylinder' 3l and downwardly through the electric field, this oil being partially dehydrated in its passage therethrough i. e. the particles of water in the emulsion are agglomerated into larger masses which are passed through the pipe 50 and the perforated pipe 5l into the settling tank. in the settling tank, the water tends to settle out into the bottoni of the tank from which it may be removed either automatically or by means of a pipe This circula? 8O controlled by a valve 81. tion of oil from the top 'of the trap tank through the treater is continued until the oil in the top of the trap tank is relatively free from water particles at which time the di-electric strength of this oil becomes so great that practically no current is taken by the treater and the dehydration ceases for lack of Water to operate on. Vilhen this condition is obtained, the valve 43 is opened and a flow of wet oil is started into the interior of the tank 1l. rll`his Wet oil flows downwardly along the inner Wall of the tank outside the edge of the deflector 50 forming a wet outer envelope or cylinder of wet oil which entirely covers the inner wall of the treater 1l. rlhis outer envelope or cylinder of Wet oil is outside and immediately adjacent to a similar moving cylinder of dry oil which is circulated by the pump l2. The result is that each of the electric fields consists of a layer of dehydrated oil inside of a layer of extremely wet emulsion. The dry oil prevents disruptive discharges between the members 32, 33 and 34 in the tank 11 at the same time promoting the dehydration.

lt will be noted that the insulator 20 projects downwardly to the center of the rapidly moving stream of dry oil which is of high enough velocity to prevent deposits from forming on the insulator thus preventing breakage of insulators. lt is sometimes necessary to circulate oil from the bottom of the settling tank 13 through the tank l1 and this may be accomplished by lowering the swing pipe vby means of the winch 54 so that oil is taken from near the bottom of the treater. The condition ,esche-e in the electric field is diagrammatically villustrated in Fig. 3 in which the small drops 90 represent water particles. it wil-l be seen that these Water particles are eX- tremely concentrated on the outside of the flowing stream being relatively few near the center.

il claim as my invention:

l. ln a dehydrator for emulsions, the combination of: a charged electrode supported in and surrounded by the emulsion to be treated; and means for surrounding said electrode with a fluid envelope of higher cli-electric strength than the emulsion to be treated.

2. ln a dehydrator for emulsions, the combination of: a charged electrode supported in and surrounded by the emulsion to be treated; and means for surrounding said electrode with a moving fluid envelope of higher di-electric strength than the emul-k sion to be treated.

3. A. method of preventing disruptive discharges between electrodes immersed in an emulsion which comprises: maintaining in the space between said electrodes a continuous layer of fluid material having a higher dielectric strength than said emulsion.

4i. ln a dehydrator, the combination of: a vessel containing the emulsion to be treated; means for establishing an electric field in the emulsion in said vessel; and means for maintaining in said field a layer of fluid material having a higher\dielectric strengththan the oil to be treated.

5. ln a dehydrator, the combination of: a vessel containing the emulsion to be treated; means for establishing an electric field in the emulsion in said vessel; 4and means Jfor maintaining in said field a moving layerv of fiuid material having a different di-electric stren th than the oil to be treated.

6. n a dehydrator, the combination of: a vessel containing the emulsion to be treated; means for establishing an electric field in the emulsion in said vessel; and means for maintaining in said field a moving layer of fluid material having a higher dielectric strength than the oil to be treated.

In testimony whereof, l have hereunto set my hand at San Francisco, California, this 18 day of Aapril 1921.

WYNN MEREQITH, 

